The present invention relates generally to gas turbine engine airfoils and more particularly to airfoils having impingement cooling.
Many conventional gas turbine engine vanes and blades have interior passages for transporting cooling air to remove heat. For instance, some conventional turbine blades have a labyrinth of interior passages through which cooling air is transported to cool the blades by convective heat transfer. Cooling holes in the surface of the blades permit the cooling air to exit the interior passages and form film cooling along the exterior surfaces of the blades. Further, some prior art blades have cooling holes extending between interior passages for directing jets of air from an upstream passage to a downstream passage so the jets impinge on an interior surface of the blades to cool the surface by impingement cooling. After impinging the surface, the cooling air is directed through film cooling holes rather than being used for additional convective cooling because it is heated too much to provide additional convective heat transfer benefit. Similarly, some prior art turbine vanes include inserts having impingement cooling holes which direct jets of air to interior surfaces of the vanes. Like the prior art blades, the cooling air is immediately exhausted through film cooling holes in the vanes after impinging the interior surface of the vanes because the cooling air is heated too much to provide additional convective heat transfer benefit.
Among the several features of the present invention may be noted the provision of an airfoil for use in a gas turbine engine. The airfoil includes a body having an interior surface defining a hollow cavity in the airfoil having an inlet and an outlet. The airfoil also includes a partition within the cavity dividing the cavity into a first cooling passage and a second cooling passage. The first cooling passage communicates with the inlet for delivering cooling air to the first passage and the second cooling passage communicates with the outlet for exhausting cooling air from the second passage. The partition has a cooling hole therein extending between the first passage and the second passage permitting cooling air to pass from the first passage to the second passage. The cooling hole is sized and positioned with respect to the interior surface of the airfoil for directing cooling air toward a portion of the interior surface of the airfoil so the cooling air impinges upon the portion. Thus, cooling air entering the inlet of the cavity travels through the first passage for cooling the body by convective heat transfer, through the cooling hole for impinging upon the portion of the interior surface of the body, through the second passage to cool the body by convective heat transfer, and out the outlet of the cavity.
Other features of the present invention will be in part apparent and in part pointed out hereinafter.